Picture frame



FIG. 1 is a front perspective view of a picture frame;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a left side elevation view thereof, the right side elevation view being a mirror image thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof.

The broken lines shown in the drawings depict portions of the picture frame that form no part of the claimed invention. 

CLAIM The ornamental design for a picture frame, as shown and described. 